1. Field of the Invention
The present invention relates to the modification of surface properties of particulate, linear, sheet-like, or three-dimensional structures, using alkoxylated polyvinylamines. The invention further relates to novel alkoxylated polyvinylamines, and also to a process for their preparation.
2. Description of the Background
Articles made from synthetic materials, such as thermosets or thermoplastics, generally have hydrophobic surface properties. However, hydrophobic properties are frequently undesirable if adhesive, or a coating or ink or paint or lacquer, is to be applied to the articles, since most adhesives, coating compositions, and paints give only inadequate adhesion to hydrophobic surfaces. Hydrophobic properties are also undesirable in textile sheets, in particular in nonwovens. Examples of uses of nonwovens are cloths for cleaning, wiping or dishwashing, and serviettes. In these applications it is important that when spilled liquids, for example, such as milk, coffee, etc. are wiped up they are rapidly and fully absorbed, and that wet surfaces are dried as fully as possible. The absorption of liquids by a cleaning cloth becomes more rapid as their transport on the fiber surface becomes faster, and fibers with a hydrophilic surface are readily and rapidly wetted by aqueous liquids.
There are various conventional processes for hydrophilicizing the surfaces of films or moldings. For example, the surfaces of plastic articles can be activated by gaseous fluorine. However, this process requires operations using the highly poisonous gas fluorine, with increased apparatus costs. Corona and plasma treatments are other processes used to increase the hydrophilic character of the surface of various materials, such as plastics or metals.
To improve the water-absorption properties of nonwovens, use is also made of surface-active hydrophilicizing agents, such as emulsifiers, surfactants, or wetting agents. These give excellent initial hydrophilic properties. However, a disadvantage of these nonwovens is that the hydrophilic agents are gradually washed out by water or other aqueous media.
After repeated contact with water, the product becomes increasingly hydrophobic. Another disadvantage of the known surface-active agents is a marked reduction in the surface tension of water so that in many applications, in particular in nonwovens used for sanitary or diaper applications, there is an undesirable increase in the susceptibility to permeation and in the wetting power of the liquid absorbed.
WO 98/27263 discloses stably hydrophilic polymer coatings for fibers made from polyester or from polypropylene or the like. The coating comprises certain polyoxypropylamines or polypropylene oxide polymers or hydrophilic polyester copolymers containing ethylene terephthalate units.
WO 97/00351 describes durably hydrophilic polymer coatings for polyester fibers, polyethylene fibers, or polypropylene fibers, and for the corresponding woven fabrics. The coatings comprise hydrophilic copolyesters, and also polypropylene oxide polymers.